1. Field of the Invention
The present invention relates to a sheet feeding apparatus for feeding sheet one by one and an image forming apparatus having such a sheet feeding apparatus and adapted to record an image on the sheet sent from the sheet feeding apparatus.
2. Related Background Art
In the past, when a sheet is supplied to an image forming apparatus to be used therewith, sheets have been fed one by one by manual feeding or sheets have been fed by a sheet feeding apparatus automatically and continuously.
When the sheet are fed one by one automatically and continuously, the sheets are normally separated one by one by means of a claw separation system using a separation claw or a friction separation system utilizing friction between the sheet and a sheet stacking means.
In order to suppress skew-feeding during the sheet separation and sheet feeding, both lateral edges of the sheet is regulated by a pair of side guides provided on the sheet stacking means.
Further, in order to enhance the regulating ability of the pair of side guides, high friction members made of rubber or sponge or biasing members are adhered to portions of the side guides with which the sheet is contacted, or, as disclosed in Japanese Patent Application Laid-Open No. 6-191650, projections are provided on the side guides.
However, the conventional sheet feeding apparatuses have the following drawbacks:
(1) In the apparatus in which the high friction members or the biasing members are adhered to the side guides, when the sheet is fed and conveyed, sliding resistance between the sheet and the side guides becomes great, which may result in skew-feeding or sheet jam.
(2) In the apparatus in which the projections are provided on the side guides, when a thick sheet such as a post card is regulated, the sheet cannot enter between the projections to create gaps between the sheet and the side guides, thereby worsening the regulating effect. Further, abutting positions between the side guides and the sheet may be changed whenever the operator manipulates the side guides, with the result that the skew-feeding cannot be prevented effectively.